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All about ERNIE

 

Who is ERNIE?

It remains a mystery who actually came up with the acronym ‘ERNIE’ to mean Electronic Random Number Indicator Equipment, but he is central to the whole concept of Premium Bonds by producing all the winning numbers.

Since 1957, the four generations of ERNIE have produced the numbers for over a hundred million tax-free prizes worth over £9 billion. 

The basic function of each ERNIE machine has not changed but, with continuous advances in technology, each ERNIE has been replaced by a faster and smaller model to keep pace with Premium Bond demand.

Then and Now – ERNIE 1 vs ERNIE 4

Ernie 1 – the original Ernie produced winning Premium Bond numbers from 1957 to 1972.	Ernie 4 – the current Ernie was introduced in 2004

If ERNIE 1 was still being used today, he would take 52 days to complete a draw, compared to the two and-a-half hours taken by ERNIE 4.

ERNIE 4, the machine that randomly draws the winning Premium Bond numbers every month, was introduced in April 2004 in anticipation of needing to generate 11-digit Bond numbers in the near future due to the popularity of Premium Bonds.  ERNIE 4 was tested and received full accreditation that he generates all Bond numbers at random regardless of their length. Therefore every Bond number, no matter whether it has eight, nine 10 or 11 digits and when it was purchased, has a separate and equal chance of winning a prize.

Please remember if you want to check for unclaimed prizes use our prize checker. NS&I does not endorse companies which charge customers a fee to search for lost or forgotten money on their behalf.

The myths about ERNIE

As with any celebrity figure, over the years some myths have grown up around ERNIE and Premium Bonds. Here are a few of them exploded.

Myth 1: “ERNIE is not random”
Each month, the Government Actuary’s Department (GAD) does an independent check on the randomness of ERNIE’s output. GAD then issues a certificate to say that it has no reason to believe that the draw isn’t random. We cannot publish numbers or pay out prizes without that certificate.

Myth 2: “You have to have £30,000 Premium Bonds to win the jackpot”
People with varying amounts of Premium Bonds have won the jackpot. For example, the winner of one £1 million jackpot had just £17 in Premium Bonds! However it is true that the more Bonds you have, the better your chances of winning. Check on our website for a full list of high value winners each month.

Myth 3: “Only new Bonds win prizes”
Each £1 Bond number has an equal chance of winning – regardless of when or where it was bought. Although Bonds bought recently seem to win more often, this is because there are many more new Bonds than old. In fact, more Bonds have been sold in the last seven years than in the previous 44 years put together.

Myth 4: “Old Bonds are left out of the draw”
As numbers aren’t entered into or stored in ERNIE, there’s no way that old Bonds can be left out of the draw. The winning numbers are generated randomly and then matched against eligible Bond numbers afterwards.

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Randomness of prize draws

Randomness is where the outcome of an event is not predetermined.

For Premium Bonds, this means that winning a prize depends on the random production of numbers by ERNIE.

Because ERNIE cannot be programmed, the numbers produced cannot be predetermined and each number produced has been generated independently of any other number. This means that each single Premium Bond number has an equal chance of winning a prize.

Each month, ERNIE produces many more numbers than prizes available. This is because some numbers produced will be for Premium Bonds not yet bought or previously cashed in.

The output of each draw is checked independently by the Government Actuary’s Department (GAD). It uses four methods of testing – Frequency, Serial, Poker and Correlation – to make sure the output has followed no set patterns, because any set pattern would suggest a bias. If no such pattern is discernible then the draw is determined to be random. A certificate is issued by GAD to say it has no reason to believe that the draw isn’t random.

Good luck from ERNIE!

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